"Police are treating the death as possibly suspicious because of the age of the little girl."

The campsite confirmed some guests were still at the site today as detectives examined the area.

Holmsley Caravan Park and Campsite has 600 pitches based on the land of a Second World War airfield on the edge of the New Forest.

Today, the blue family tent where the incident took place remains sealed off by police.

One witness, who did not want to be named, said she was woken by the sound of screams and someone repeatedly pressing a car horn before police and paramedics arrived at the scene.

Sgt McNicol added that forensic teams have not yet entered the tent to start their investigations.

She said: "When a six-year-old child is found, then initially we have to think it's a suspicious death.

"But until there is a full post-mortem examination, we do not know what the cause of death was.

"There is a long way to go before we know if there's any foul play. But whether it's foul play or not, it's a tragedy."

She reassured fellow campers that no-one else is at risk.

A Hampshire Police spokeswoman said a post-mortem examination will take place later today.

The spokeswoman added that the detained couple are still being interviewed today and police are liaising with family members of the dead youngster.

Campers close to where the incident occurred were moved by police this afternoon and the campsite is closed to new admissions, with those who have booked for the Easter holiday contacted directly and told not to come.

A woman at the entrance told reporters: "We don't really want to stay anymore and will be leaving.

"The mood in the campsite is really sombre and it feels that we should not be here.

"Lots of people have been leaving."

A fellow camper told the Southampton Echo they had no idea about the girl's death, saying: “Blimey, you come away on holiday for Easter and then something like this happens.”